My trailer is a 2008. I made one trip of 800 miles just after I got it. Otherwise all our camping trips are about 40 miles or less. I don't think I have 5000 miles total on the trailer. So the que...
Everyone has their own maintenance schedules that work for them... I do mine every other year now. For the first couple of years I did them each year, but found that every other year works best for me.. ;)
I don't think it's the actual miles that matter.. It's the time they sit idle and the conditions they are "idle" in...
After 6 years, I'd say I'd at least want to look at them just for my own peace of mind..